The spot that blocks a whole table
Some spots touch, or share a row or column with, every free spot of a small table. A cup there would leave that table with nowhere to go, so the spot gets an X.
Before
After
How to spot it
- Start from a small table with two or three free spots.
- Look at the spots right next to it, and at the row or column its spots share.
- Ask for each nearby spot: if a cup stood here, would this table still have a free spot? If not, cross it out.
Why it works
A cup crosses out its whole row, its whole column and the eight spots around it. If that wipes out every free spot of some table, that table can never get its cup, and the puzzle would break. So no cup can stand there.
Try it on a real board
Play a free board in your browser, no account needed. When you are stuck, the hint shows where to look, then explains the step.
The Brewdoku app has 300 levels that bring in these steps one at a time, from small boards to 10x10, and a hint that shows where to look, then why, and only then makes the move.
